Numerous examples of optical ranging systems have been proposed by workers in the art, and reference can be made to a basic triangulation system disclosed in U.S. Pat. No. 4,627,734 issued Dec. 9, 1986 to Marc Rioux. Further explanation of the theory behind this system and some practical applications are provided by "Laser range finder based on synchronized scanners" by M. Rioux, published in Applied Optics, Vol. 23, No. 21, pp 3837-3844, Nov. 1, 1984.
An alternative ranging system is disclosed in "Compact three-dimensional camera for robotic applications" by M. Rioux et al., published in Journal of the Optical Society of America, Vol. 3, page 1518, September 1986; and many of the practical applications of the various different types of ranging systems are set out in "Range Imaging Sensors Development at NRC Laboratories" by M. Rioux et al., published in Proceedings of the Workshop on Interpretation of 3D Scenes, Austin, Tex., Nov. 27-29, 1989.
With the explosive development of virtual reality and the need for environment modelling facilities, optical surface scanners are becoming extremely useful tools. These sensors can provide precise surface shape as well as surface color in some cases. However, most of the currently existing scanners are bulky, or have been devised for fixed-mount or tracking arm operation. The current motivation is to make a compact hand-held sensor technology widely available.
Although laser sensors based on sequential scanning can provide good precision measurements in stable operation, the recovered surface becomes noisy and distorted when there is camera motion due, for example, to an insufficiently rigid mount or to involuntary hand motion when the camera is hand-held. To compensate for camera motion, the current existing prototypes integrate a global positioning system, instruments or restrictive assumptions on the observed shape. See, for example, "A hand-held optical surface scanner for environmental modeling and virtual reality" by R. B. Fisher et al., presented at the Virtual Reality World '96 Conference in Stuttgart, Germany, Feb. 13-15, 1996; and "Registration of Multiple Overlapping Range Images: Scenes without Distinctive Features" by K-P. Bohroog et al., published in IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 13, No. 9, pp. 857-871, September 1991, which used stripped images. Unfortunately, these solutions to the problem have not proved sufficiently precise and appropriate for general applications. Moreover, hardware complexity may increase.